Duplicate edit bones
There is no bone.duplicate_move  There is a bpy.ops.armature.duplicate(...) but being an operator it wont return the newly created bone(s) only a status set.  {'FINISHED'} if run succesfully for instance.

Need something like (run in edit mode ofcourse)

import bpy
arm = bpy.context.object.data
for b in arm.edit_bones[:]:
    cb = arm.edit_bones.new(b.name)

    cb.head = b.head
    cb.tail = b.tail
    cb.matrix = b.matrix
    cb.parent = b